Impact of Distributed Urban Diesel Generators on Household Exposure to Carcinogenic Airborne Particles during Rolling Blackout Episodes

Marc Al Helou(1), Ezzat Jaroudi(1), ALAN SHIHADEH(1)

(1) American University of Beirut

     Abstract Number: 483
     Last modified: May 13, 2010

Abstract
Environmental regulations in the global South are often lax or laxly enforced. In Lebanon, the national electric power producer has had in effect in recent years a regime of rolling daily blackouts due to limited production capacity. Households and businesses have therefore turned to privately owned diesel generators operating at the neighborhood- or individual building-level to provide power during these outages. A large fraction of them exhaust at street level. In Beirut, which is characterized by a dense, vertical urban morphology, emissions from private diesel generators during power outages may lead to elevated human exposure levels of airborne carcinogens. To examine this potential unintended consequence of electric power rationing, a self-powered portable air and electricity monitoring system was developed and installed on the balconies of apartments in Beirut for 7 days of continuous monitoring. The system includes a CPC (TSI 3007) for logging ultrafine particle (UFP) concentrations, and a particle-polyaromatic hydrocarbon (PPAH) monitor (EcoChem PAS 2000). This real-time monitoring approach allows tracing a causal relationship between elevation in ambient UFP and PPAH concentrations and the operating state of proximal diesel generators. We found that the PPAH and CPC signals were highly inter-correlated, and that regardless of the time of day PPAH and UFP concentrations rise significantly whenever the national power is interrupted. Although the power is interrupted less than 3 hours per day, diesel generators contributed 8-30% increase in 24-hour PPAH household exposure burden. Using a Lagrangian pollutant dispersion model for building complexes (QUIC PLUME), effects of generator scheduling and stack height on household exposure levels were explored as policy options for reducing the impact of distributed diesel generators.