Quantified Health Impacts of Air Pollution Exposure

This page reviewed November 23, 2009

Although the health effects from exposure to air pollutants have been known for some time (see table below), the Air Resources Board (ARB) has only recently begun to quantify the impacts on a statewide basis. There is a large body of scientific evidence that ties fine particulate matter (PM2.5) with shortened life spans, heart attacks, asthma attacks, missed work days and other health impacts. The ARB relies on effect estimates from published, peer-reviewed studies that relate health effects to ambient concentrations of PM. These studies inform us about the relationships between increases in air pollutants and increases in adverse health conditions. Further, the ARB has ambient air monitoring stations throughout California that provide information about pollutant concentrations. By using these measured concentrations of ozone or PM in the air, we can estimate the health impacts associated with public exposures to unhealthy levels of PM and ozone. The table below summarizes the health impacts, followed by links to analyses we have conducted.

Annual California PM2.5 and Ozone Health Impacts

Health Outcome	Cases per Year	Uncertainty Range¹ (Cases per Year)	Valuation²(Millions)	Uncertainty Range³ (Valuation - Millions)
Premature Death	19,000	6,000 to 33,000	$170,000	$55,000 to $300,000
Hospital Admissions (Respiratory & Cardiovascular)	9,400	5,600 to 14,000	$370	$220 to $540
Asthma and Other Lower Respiratory Symptoms	280,000	110,000 to 430,000	$5.6	$2.3 to $8.6
Acute Bronchitis	22,000	0 to 44,000	$10	$0 to $20
Work Loss Days	1,900,000	1,600,000 to 2,100,000	$370	$310 to $420
Minor Restricted Activity Days	13,000,000	9,700,000 to 16,000,000	$830	$620 to $1,000
TOTAL VALUATION	NA	NA	$170,000	$56,000 to $300,000

¹Range reflects uncertainty in health concentration-response functions, but not in exposure estimates.
²Economic valuations are for the year 2009 (in undiscounted 2007 dollars). These numbers will be updated as new valuations become available.
³Range reflects uncertainty in health concentration-response functions for morbidity endpoints and combined uncertainty in concentration-response functions and economic values for premature death, but not in exposure estimates.

Note: Results in this table are based on 2004-2006 PM2.5 concentrations above 5 µg/m³ and 2004-2006 ozone measurements not meeting the California 8-hour standard of 0.070 ppm.

		Ambient PM2.5 (Particulate Matter 2.5 µm or less in diameter)
		Exposure to particulate matter has been associated with premature death and cardiorespiratory diseases. Details about the methodology for determining premature death associated with PM2.5 exposure can be found at this link. Refer to Chapter 9 of the Review of the Ambient Air Quality Standards for Particulate Matter and Sulfates to learn about the general methodology for quantifying PM2.5-related health impacts.
		Ambient Ozone
		Ozone exposure can lead to reduced lung function and increased respiratory symptoms; it is even associated with illness and premature death. A description of the methods used to calculate health risks from ozone can be found at this link. This link leads to the revised Ambient Air Quality Standards for ozone, which includes quantification of health impacts. For additional details on quantified impacts from ozone, see: BD Ostro, H Tran & JI Levy. 2006. The Health Benefits of Reduced Tropospheric Ozone in California. Journal of the Air & Waste Management Association 56:1007-1021.
		Goods Movement
		Transport of goods via California's ports, rail systems, and roads may have major environmental impacts. Click on this link to read details about the approved Emission Reduction Plan for Ports and Goods Movement, for which health impacts were calculated.
		Diesel Particulate Matter
		Exposure to diesel exhaust particulate matter can be associated with premature death and cancer as well as other health problems. An overview of ARB's efforts to reduce diesel emissions may be viewed at this link. More information about the health impacts of diesel particulate matter can be found at this link. This link provides details about ARB's Carl Moyer Clean Engine Incentive Program, which encourages new clean-technology engines. For additional details on diesel impacts, including ARB's risk calculations, see: AC Lloyd & TA Cackette. 2001. Diesel engines: environmental impact and control. Journal of the Air & Waste Management Association 51:809-847.

For more information, please contact Dr. Linda Smith at lsmith@arb.ca.gov or (916) 327-8225.

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Quantified Health Impacts of Air Pollution Exposure