Setting the standard: The acceptability of kitchen ventilation for the English housing stock

Exposure to particulate matter with diameter ≤2.5 μm (PM_2.5) is associated with an elevated risk of adverse health effects and cooking is a primary source of PM_2.5 in non-smoking households. Therefore, it is important to investigate PM_2.5 concentrations that might be found in domestic kitchens, and the appropriate ventilation mechanisms to reduce them. Uncertainty in daily mean PM_2.5 concentrations in English kitchens is predicted using a statistical model and stochastic simulation. A worst-case heating season scenario is considered where 3 meals are cooked per day and fresh air is provided by infiltration and fans. The model predicts that >98% of English houses are too airtight to dilute PM_2.5 emissions solely by infiltration so that daily mean concentrations in kitchens are below the WHO guideline of 25 μg/m³. Therefore, controlled ventilation is required in all kitchens. Ventilation strategies prescribed by English Building Regulations and ASHRAE 62.2 are found to be adequate for <12% and 75% of houses, respectively, when applied during cooking. Continuing to ventilate for a further 10 minutes has a significant effect when using an intermittent strategy, increasing the centiles of compliant houses to 46% and >98%, respectively. A cooker hood is the most effective ventilation strategy when used during cooking plus 10 minutes. Standards should be amended to incorporate required combinations of airflow rates and capture efficiencies. A hood with a capture efficiency of 50% requires airflow rates of 52 l/s and 90 l/s for PM_2.5 concentrations to remain below WHO guidelines in 75% and 98% of houses, respectively.