|Information for patients with allergy and related
in the Southwest
Environment and allergic disease
Air Pollution, Asthma and Allergy
Which Air Pollutants Cause Respiratory Disease?
Symptoms of asthma and other chronic lung diseases are often precipitated by increased
levels of air pollutants including particulates, nitrogen oxides, ozone and sulfur
dioxide, all of which may directly irritate the airways. The increased
incidence of asthma in the fall and winter is probably due to several factors including
the effects of temperature inversion on vehicle-generated pollution, combined with the
increased incidence of respiratory virus infection at this time of the year, and increased
mold spore counts.
The incidence of allergic respiratory disease is high and continues to increase in
populations of urban areas of Westernized countries throughout the world. There is
mounting evidence from epidemiologic and laboratory research of an important cause of
allergy in Westernized civilizations: protection from bacterial exposure and bacterial
infection in childhood through hygiene and liberal use of antibiotics. Certain
bacterial products appear to affect the developing immune system in childhood by diverting
immune responses away from allergy. Another explanation of this public health
problem in developed countries is air pollution from automobile traffic.
Diesel exhaust, known to boost the formation of IgE antibodies in experimental animals to
make them allergic, could play a part in causing allergy in human populations.
Although air pollution is an important trigger for asthma symptoms, it is not
considered to be an important cause of allergy as such, because of the low incidence of
allergy in polluted non-Western environments.
Air Pollution in Arizona
Metropolitan Tucson is surrounded by mountains, predisposing the area to frequent
temperature inversions. During this time the valley fills with colder air containing
higher concentrations of air pollutants, as compared with mountain slopes above the
temperature inversion layer. Air pollution in Maricopa County (which includes
Phoenix) is considerably higher than that in Tucson.
Air pollutants in Arizona cities are principally nitrogen oxides, ozone, carbon monoxide
and particulates. Local sources of air pollution are traffic (greater than 40%),
vehicle-generated paved road dust (12%), and dust from unpaved roads (8-10%).
Pollution from automobile emissions (mainly nitrogen dioxide) increases in the winter,
particularly on days with temperature inversion. As in other cities, use of
oxygenated motor fuels contributes to aldehyde and other volatile organic compound
pollution. Detailed daily information on air quality in Arizona can be found on
the web sites for Pima County, Maricopa County
Air Pollution in Tucson
The average concentration of ozone in the city ranges from 0.022 to 0.042 ppm (parts per
million) throughout the Tucson basin, and is tending to increase. Highest levels of
ozone generally occur in the summer, and increase during the afternoons when the
temperatures are high. Average concentrations of nitrogen dioxide range from 0.019
to 0.021 ppm, and particulates 10 microns and smaller range from 12.5 to 30.7 micrograms
per cubic meter. Aside from a coal-fired power plant, Tucson has no heavy
industrial sources of sulfur dioxide and levels of this pollutant are low.
For details on levels of ozone, nitrogen dioxide, carbon monoxide, sulfur dioxide and
particulates (PM10 and PM2.5) based on current monitoring in Tucson and other localities
as compared with all other monitoring stations in the country, go to
Air inside an air-conditioned home in which there are no smokers, pets or old carpets is
usually free of hazardous levels of air pollutants that could cause respiratory disease.
In the Southwest evaporative coolers, commonly used instead of refrigerated
air conditioning, can increase indoor levels of airborne allergens, particularly mold
spores. Tobacco smoke, pets (particularly cats), house dust mites, cockroaches and
moldy carpet are common indoor triggers of asthma and rhinitis.
Additional information on air pollution, greenhouse gases, global warming and
outdoor air quality may be found on the web sites of the Environmental Protection Agency and
Environmental Protection Agency. The Californian site provides
well-written information in excellent detail.
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Disclaimer: This site is for educational
purposes only. Any information that you have found in this web site is not
intended to replace medical care or advice given to you by your own physicians. You should
consider consulting your local medical library and other web sites for additional
Comments and suggestions welcome! Email: firstname.lastname@example.org
Content Owner: Michael J. Schumacher, MB, FRACP, The
University of Arizona