Effect Of Ventilation On Chronic Health Risks In Schools And Offices

Abstract

This study provides a risk assessment for chronic health risks from inhalation exposure to indoor air pollutants in offices and schools with a focus how ventilation impacts exposures to, and risks from, volatile organic compounds (VOCs) and particulate matter (PM2.5). We estimate how much health risks could change with varying ventilation rates under two scenarios: (i) halving the measured ventilation rates and (ii) doubling the measured ventilation rates. For the hazard characterization we draw upon prior papers that identified pollutants potentially affecting health with indoor air concentrations responsive to changes in ventilation rates. For exposure assessment we determine representative concentrations of pollutants using data available in current literature and model changes in exposures with changes in ventilation rates. As a metric of disease burden, we use disability adjusted life years (DALYs) to address both cancer and non-cancer effects. We also compare exposures to guidelines published by regulatory agencies to assess chronic health risks. Chronic health risks are driven primarily by particulate matter exposure, with an estimated baseline disease burden of 150 DALYs per 100,000 people in offices and 140 DALYs per 100,000 people in schools. Study results show that PM2.5-related DALYs are not very sensitive to changes in ventilation rates. Filtration is more effective at controlling PM2.5 concentrations and health effects. Non-cancer health effects contribute only a small fraction of the overall chronic health burden of populations in offices and schools (<1 DALY per 100,000 people). Cancer health effects dominate the disease burden in schools (3 DALYs per 100,000) and offices (5 DALYs per 100,000), with formaldehyde being the primary risk driver. In spite of large uncertainties in toxicological data and doseresponse modeling, our results support the finding that ventilation rate changes do not have significant impacts on estimated chronic disease burdens. Median estimates of DALYs are approximately doubled when the ventilation rates are halved and there is little reduction in health risks associated with doubling ventilation rates, but the very low baseline disease burden from the indoor exposures we considered makes this unremarkable. In exploring the full range of exposure concentrations, to find the fraction exceeding the Office of Environmental Health and Hazard Assessment's (OEHHAs) chronic reference exposure levels (cRELs) and United States Environmental Protection Agency's (USEPA) chronic reference dose (RfD) we found only minor shifts in exposure safety margins when ventilation was doubled or halved. We combined our exposure estimates with cancer potency factors published by OEHHA and USEPA to determine that the annual excess cancer risk per capita are below 1 in a million under all ventilation rate scenarios for individual pollutants. The results indicate that chronic health risks (cancer and non-cancer) associated with VOC and PM2.5 exposure in offices and schools are low and thus t...

Developing evidence-based prescriptive ventilation rate standards for commercial buildings in California: a proposed framework

“…Formaldehyde is the primary driver of cancer risk in offices . Workplace lifetime cancer risk estimates for offices, using California OEHHA cancer potency factors (Office of Environmental Health Hazard Assessment 2009) with the method of Parthasaranthy et al (2013), are 1.9 x 10 -5 and 1.6 x 10 -5 , for the Title 24 and ASHRAE 62.1-2010 MVRs at default occupancies, respectively. These are just above the risk level of approximately one in 10 -6 that is considered sufficient to justify regulation or corrective measures (Travis et al 1987).…”

“…With support from the California Energy Commission, researchers at Lawrence Berkeley National Laboratory (LBNL) are performing extensive research exploring relationships between VRs, indoor contaminant emission rates, indoor contaminant concentrations, exceedances of contaminant concentration guidelines, and associated chronic health risks (Apte et al 2012;Chan et al 2012;Dutton et al 2013;Parthasaranthy et al 2012bParthasaranthy et al , 2013. Also, the direct relationships of VRs with several human outcomes are being studied.…”

“…Recent summaries of available evidence on associations between VRs and performance in offices and schools are provided by the IAQ Scientific Findings Resource Bank page on Impacts of Building Ventilation on Health and Performance (Fisk 2013a Parthasaranthy et al (2012b) identified VOCs that are present in commercial buildings (e.g., (Bennett et al 2011; U.S. Environmental Protection Agency 2013a)) at levels approaching established guidelines and standards and for which indoor air concentrations are affected by VRs. Parthasaranthy et al(2013) subsequently estimated the increased cancer risks and noncancer chronic health risks of these VOCs at different VRs using cancer potency information from California OEHHA and the U.S. EPA.…”

Evaluation of the Indoor Air Quality Procedure for Use in Retail Buildings

“…A complementary effort (Parthasarathy 2012b) is estimating the chronic health risks for a range of VRs in retail and other types of buildings. These studies are parts of a larger research effort designed to provide a stronger scientific basis for ventilation standards that balance energy efficiency with provision of acceptable indoor environments for occupants.…”

Integrated Technology Air Cleaners (ITAC): Design and Evaluation

“…In general, to enable reductions in ventilation rates and associated energy savings, VOC air cleaning methods must be effective for the spectrum of indoor-generated VOCs that have concentrations affected by ventilation rates and that are known or suspected to be important for health (Parthasarathy, Chan et al 2012). While the identity of all important VOCs is uncertain, analyses are starting to identify the key VOCs, and these analyses indicate that the risks of formaldehyde will often be dominant among the chronic health risks of indoor VOCs (Logue, McKone et al 2011, Logue, Price et al 2012, Parthasarathy, Fisk et al 2013. Analyses also indicate that particles in indoor air, arising from outdoor air and from indoor sources, likely pose the largest risks of chronic health effects from indoor air pollutants in homes (Logue, McKone et al 2011, Logue, Price et al 2012.…”