Healthy Zero Energy Buildings (HZEB) Program - Cross-Sectional Study of Contaminant Levels, Source, Strengths, and Ventilation Rates in Retail Stores

Abstract

This field study measured ventilation rates and indoor air quality parameters in 21 visits to retail stores in California. The data was collected to guide the development of new, science-based commercial building ventilation rate standards that balance the dual objectives of increasing energy efficiency and maintaining acceptable indoor air quality. Data collection occurred between September 2011 and March 2013. Three types of stores participated in this study: grocery stores, furniture/hardware stores, and apparel stores. Ventilation rates and indoor air contaminant concentrations were measured on a weekday, typically between 9 am and 6 pm. Ventilation rates measured using a tracer gas decay method exceeded the minimum requirement of California's Title 24 Standard in all but one store. Even though there was adequate ventilation according to Title 24, concentrations of formaldehyde, acetaldehyde, and acrolein exceeded the most stringent chronic health guidelines. Other indoor air contaminants measured included carbon dioxide (CO 2), carbon monoxide (CO), ozone (O 3), and particulate matter (PM). Concentrations of CO 2 were kept low by adequate ventilation, and were assumed low also because the sampling occurred on a weekday when retail stores were less busy. CO concentrations were also low. The indoor-outdoor ratios of O 3 showed that the first-order loss rate may vary by store trade types and also by ventilation mode (mechanical versus natural). Analysis of fine and ultrafine PM measurements showed that a substantial portion of the particle mass in grocery stores with cooking-related emissions was in particles less than 0.3 µm. Stores without cooking as an indoor source had PM size distributions that were more similar indoors and outdoors. The whole-building emission rates of volatile organic compounds (VOCs) and PM were estimated from the measured ventilation rates and indoor and outdoor contaminant concentrations. Mass balance models were then used to determine the ventilation rates, filtration strategies, or source reductions needed to maintain indoor contaminant concentrations below reference levels. Several scenarios of potential concern were considered: (i) formaldehyde levels in furniture/hardware stores, (ii) contaminants associated with cooking (e.g., PM, acrolein, and acetaldehyde) in grocery stores, and (iii) outdoor contaminants (e.g., PM and O 3) impacting stores that use natural ventilation. Estimated formaldehyde emission rates suggest that retail stores would need to ventilate at levels far exceeding the current Title 24 requirement to lower indoor concentrations below California's stringent formaldehyde reference level. Given the high costs of providing ventilation but only modest chronic health benefit is expected, effective source control is an attractive alternative, as demonstrated by some retail stores in this study. Predictions showed that grocery stores need MERV 13 air filters, instead of MERV 8 filters that are more commonly used, to maintain indoor PM at levels that meet the chronic he...

Estimated effect of ventilation and filtration on chronic health risks in U.S. offices, schools, and retail stores

“…The 3‐year averaged C out was used for calculating C in as described in Equations 1 and 2. For d‐limonene, as data were not available from U.S. EPA, the average outdoor concentrations measured by three studies (Bennett et al., ; Chan et al., ; Siegel et al., ) were used instead.…”

“…A third way of estimating mean indoor concentrations using maximum-likelihood estimates (MLE) and assuming lognormal distribution also gave similar results. Measurements of VRs were reported in the referenced studies (Bennett et al, 2011;Chan et al, 2014;Persily and Gorfain, 2008;Siegel et al, 2012), with the exception of the California Portable Classroom study (CARB, 2004), where the ventilation rates were not directly measured but calculated from indoor and outdoor CO 2 measurements as per Mendell et al (2013). For the calculation of indoor pollutant concentrations as a function of VRs, measurements of VRs were converted to an air exchange rate, k (1/h), which is the outdoor air supply rate normalized by building volume.…”

IAQ and energy impacts of ventilation strategies and building envelope airtightness in a big box retail building

“…Most buildings in the Bennett et al [8] study did not meet California's Title 24 minimum requirements for ventilation on a per area basis. Chan et al (2012Chan et al ( , 2014) conducted a study of retail stores in California, which showed that HCHO concentrations exceeded the OEHHA REL, and that acetaldehyde and acrolein levels exceeded the reference concentration for chronic inhalation exposure (RfC) issued by the U.S. EPA [10] while meeting or exceeding the Title 24 minimum ventilation requirement of 7 L/s person or 1 L/s m 2 . The highest levels of HCHO were measured in apparel stores, and acetaldehyde and acrolein were highest in grocery stores.…”

Cooking‐related PM 2.5 and acrolein measured in grocery stores and comparison with other retail types

“…More detail descriptions of the stores sampled and data summaries can also be found in Chan et al. ().…”

“…Results of measurements of volatile organic compounds (VOCs), ozone, and ventilation rates are described in Chan et al (2014a). More detail descriptions of the stores sampled and data summaries can also be found in Chan et al (2014b).…”