Local topography and weather conditions are ideally suited to the generation of air pollution. Los Angeles' cherished, yet pollutant-trapping, ring of mountains set the stage for a dilemma long before millions of cars and trucks filled our freeways. Indeed, lore has it that early inhabitants referred to the San Gabriel Valley as the "Valley of Smokes" - and on many days that name still seems apt. Despite extensive emission control efforts that significantly improved Los Angeles ' air quality over the last 30 years, views of thick haze obscuring downtown skylines remain a familiar sight.
Regulations Cut U.S. Carbon Monoxide Emissions
Industry, an ever-growing population, and more than 12 million vehicles, pose a formidable challenge for regulatory agencies trying to achieve and maintain air quality standards designed to protect human health. Six major air pollutants, referred to as "criteria pollutants" - ozone, particulate matter, carbon monoxide, nitrogen dioxide, sulfur dioxide, and lead - are routinely monitored for compliance with air pollution standards.
The South Coast Air Basin remains in violation of the ozone, particulate matter, and carbon monoxide standards. Ozone and particulate matter are considered the most critical to human health. Some progress has been made in reducing levels of particulate matter since ; more significant reductions have been achieved in reducing ambient ozone.
In , there were a staggering Stage 1 smog episodes in the South Coast Air Basin ; in , there were only 12 such episodes. Stage 1 episodes are defined as the level where air pollution is considered to be "very unhealthful" ozone above parts per billion. Despite the sharp reductions, ozone levels violated the federal standard ppb on 62 days, and the state standard 90 ppb on separate days.
Along with the downward trend in concentrations of some pollutants over the past decade, another change is occurring. The worst ozone used to be in the eastern San Gabriel Valley ; today the highest observed ozone concentrations are in the Central San Bernardino mountains.
A Air Quality Management District AQMD study finds an ironic reason for the geographic shift: better emission controls and new fuel formulations are reducing volatile pollutants such as vehicle exhaust or paint fumes and causing them to react more slowly in intense sun. As a result, when pollutants build up in the traffic-congested western edge of the air basin, it takes longer to turn them into smog. By the time a chemical reaction occurs, the sea breezes have blown the smog all the way out toward the mountains. Children are believed to be especially vulnerable due to higher relative doses of air pollution and increased susceptibility as their lungs develop and their bodies grow.
In the past, rare severe air pollution episodes have been associated with increases in both child and adult mortality rates. Acute or short-term effects of air pollution are also well-documented at levels of pollutants similar to those that children breathe on a smoggy Southern California day. Air pollution is linked to multiple adverse health effects in children, among them increased respiratory symptoms and hospitalizations for respiratory illnesses, increased or more severe asthma episodes, decreases in lung function, and longer-lasting lung infections.
High levels of ozone and fine particulates are specifically linked to aggravation of children's asthma. Exposure to particulate matter is associated with increased lung irritation and respiratory symptoms in children, together with decrements in lung function. In an attempt to clarify the relationship between air pollution and chronic respiratory health effects in children, researchers at the USC Keck School of Medicine are measuring pollutant levels in 12 Southern California communities, and tracking the respiratory health of more than 3, students.
By comparing children's health in communities with different pollution profiles for four major air contaminants ozone, particulates, nitrogen dioxides, and acids , researchers hope to pinpoint which pollutants are linked to specific health problems. Particulate matter and nitrogen dioxide appear to be the most strongly associated with the development of chronic lower respiratory symptoms in asthmatic children. Initial results indicate that exposure to pollutants retards the growth of lung function in children.
Nitrogen dioxide perhaps as an indicator of exposure to traffic exhaust appears to be most highly associated with this effect in young children See Box 2. An area Fig. The central dimensions of the study domain are km E-W and km N-S. The Titiwangsa Mountain is a range from the Malaysia—Thai border in the north running approximately south-southeast over a distance of km forms the backbone of the Peninsular and separating the western part from the western part. The highest average temperatures are at April-May and July-August in most places, and the lowest average monthly temperatures are at November-January.
There is a definite variation of monthly mean temperature coincided with the monsoons, the annual fluctuations of roughly 1. The monsoons significantly affect the climate of Peninsular Malaysia. During the inter-monsoon months usually occur in April and October , the wind light and variable, and thunderstorms develop causing Substantial rainfall in each of the two transition periods, especially in the west coast states. Monsoon changes as well as the effects of topography are the main factors that affect the rainfall distributions.
Maximum rainfall is occurred near the end of the year during the early NEM in most of the areas, while second maximum rainfall during the intermonsoon months April or May. The high intensity rainfall is absolutely absent during the SWM period except in the west coastal stations.
Committee on Carbon Monoxide Episodes in Meteorological and Topographical Problem Areas
The lowest monthly rainfall occurs in February, and the highest monthly rainfall in December Varikoden et al. The first new generation of meteorological advanced sounders for operational and research use was AIRS, one of several instruments onboard the EOS Aqua spacecraft launched May 4, AIRS instrument and its two companions microwave instruments, the Advanced Microwave Sounding Unit AMSU and the Humidity Sounder for Brazil HSB , form the integrated atmospheric sounding system are characterizing and observing the entire atmospheric column from the surface to the top of the atmosphere in terms of temperature and surface emissivity, cloud amount and height, atmospheric temperature and humidity profiles and the spectral outgoing infrared radiation Fishbein et al.
The Aqua spacecraft coverage is pole-to-pole, and covers the globe two times a day, at orbit is polar sun-synchronous with a nominal altitude of km miles and an orbital period of The platform equatorial crossing local times are in the afternoon ascending and in the morning descending. Also, provides integrated column burden for several trace gases Chahine et al.
Figure 2. AIRS is a continuously operating cross-track scanning sounder, consisting of a telescope that feeds a scale spectrometer. Level 1A, Level 1B and Level 2 produce granules of different products every day. Each product granule contains six minutes of data Ye et al. Level 3 products are statistical summaries of geophysical parameters that have been temporally aggregated and spatially re-sampled from lower level data products e. When there is no coverage for that day, the daily Level 3 products will have gores between the satellite paths. The weekly Level 3 products may have missing data because of data dropouts.
Monthly Level 3 products will probably contain complete global coverage with little missing data and without gores Aumann et al. Level 1, Level 2 and Level 3 data set products. Jason, The study has been carried out for daily [six-day August and six-day August ], and monthly data. In order to evaluate and analysis the impact of Indonesia forest fire on CO distribution, and the monthly CO distributions in the study area.
Generally, twelve daily and twelve monthly L3 ascending granules were downloading to obtain the desired output. Data including the corresponding location and time along the satellite track in a HDF Hierarchical Data Format format on monthly basis. To better assess the impacts and distribution of CO above Peninsular Malaysia, the maps of CO were generated by using Kriging interpolation technique for the daily August and , and monthly The skies over Peninsular Malaysia were noticeably hazier than normal on mid-August In this section, we examine the impact of one smoke transport event on CO levels in Peninsular Malaysia.
The elevated levels of CO found in smoke plumes from incomplete combustion of forest fires can lead to important further CO production downwind of the fires. To better assess the influences of forest fires and the transport smoke filled air mass on the local air quality in Peninsular Malaysia.
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The six maps in Fig. It observed an elevation in the CO values higher than normal rates during the period from mid-July to mid-August in Malaysia Rajab et al. From Fig. Plainly evident the CO total column values are high in 12 August, increase to be highest in 14 August, and a gradual decrease of CO values after 16 with a reduction impact of the forest fire, compared to previous days DOE, The highest value was when the hazy conditions reached its peak on 12 August over Selangor 2.
The lowest value of CO was on 23 August over Terengganu 1. Selangor and Negeri Sembilan , Penang and Johor. Enhanced CO values in Selangor on 13 August 1. The greater draw down of CO total column occurs over pristine marine environment in the north east coast of Terengganu and in the Inland region of north Kelantan 1.
To illustrate the biases between the two data sets, which are caused by biomass burning, the daily August and zonal averaged CO total column is showed in Fig. In Fig. It can be seen clearly, in all the stations the daily CO concentration on August is higher than August There is a clear difference between two lines, especially in 14 August when the impacts of forest fire up to a maximum.
The discrepancies become less after 17 August with a lower impact of fires. In general, south to north the CO values differences are larger than West to East between two lines over study areas. The largest differences are in the north regions uppers the latitude 4. Based on the combination of rich local sources of CO along with the transport of additional significant amount of pollution from Siberia and northeast Asia brings in the beginning of the northeast monsoon led to increase the values of CO at early dry season Pochanart et al.
Plainly evident the impact of peatland fires in several areas in Sumatra, Indonesia, on the values of CO in the north and central of Peninsular Malaysia during January, with continuing its impact on the central and southern regions during February. Unusually, there was a decrease in the values of CO at the end of the dry season during March-April due to unexpected reasonable rainfall during this period throughout the Peninsular Malaysia Malaysian Meteorological Department, The highest value of CO in dry season was 2.
The strong effects of regional biomass burning during the dry season, a regular annual occurrence in January to April, makes it extremely difficult to detect any evidence of the long-range transport of air pollution to Southeast Asia from other regions Pochanart et al. Normally, in the late dry season, large regional biomasses burning occur and the impact of air masses pollution transport has significant from the western Asia, Middle East and East Asia Pochanart et al.
The subtle differences peak of biomass burning indicate differences in transport patterns as well as differences in rainfall patterns across the region, the enhanced CO emission correlates with occasions of less rainfall McMillan et al. Additionally, the lack of rain results in long carbonaceous lifetimes, this lengthens the time during which oxidation reactions can take place Rasch et al. In the late wet season August-October , observed moderate value in the north regions, upper the latitude 5, while slightly high to high values in the rest of regions due to the impact of peatland fires from Sumatra and transboundary pollution which was aggravated by hot weather conditions DOE, The highest value was 2.
During the summer monsoon wet season May - October, the marine air masses from the middle and low latitudes of the Southern Hemispheric Indian Ocean are dominated continental Southeast Asia. These marine air masses carry small to moderate amounts of air pollution to southwest Asia. In addition, less regional biomass burning occurred and the impact of air masses is less significant from the Pacific and Indian Oceans Pochanart et al. In short, observed the highest values of CO occurred when biomass burning during dry season, and also over the industrial and congested urban zones it is the most abundant pollutant in urban atmosphere and very stable, having an average lifetime of about two months where the main source of emission was vehicles which contributed to 95 percent of CO emission load in Malaysia during DOE, ; Kopacz, et al.
A greater draw down of the CO occurs over the pristine continental environment in the northeast region regions on June at Perak This was due to lack of sources CO as well as the direct influence of south westerly wind, which remove polluting gases continuously CO slightly lighter than air Jasim et al. Furthermore, the rain is a great cleanser of the atmosphere so the Hoskins, Draxler, R.
Atmospheric Environment , 25A : — Finlayson-Pitts B.
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Atmospheric Chemistry: Fundamentals and Experimental Techniques. New York: Wiley. Garratt J. The Atmospheric Boundary Layer.
- Understanding Air Quality.
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Cambridge: Cambridge University Press. Gifford, F. Modelling urban air pollution. Atmospheric Environment , 7 : — Girardi, F. Guenther, A. A global model of natural volatile organic compound emissions. Journal of Geophysical Research , : — Holzworth, G. Climatological Aspects of the Composition and Pollution of the Atmosphere.
Technical Note No. Geneva: World Meteorological Organization. Third Assessment Report. Climate Change The Scientific Basis. Houghton, J. New York: Cambridge University Press. Khandekar, M. Natural Hazards , 21 2—3 : — Jacobson, M.
Fundamentals of Atmospheric Modelling. Atmospheric Pollution: History, Science and Regulation. Lettau, H. Physical and meteorological basis for mathematical models of urban diffusion. Proceedings of symposium on multiple source urban diffusion models. Air pollution control official publication No.
McKendry, I. Journal of Geophysical Research — Atmosphere , D16 : — Oke, T. Boundary Layer Climates. Canada: Routledge.