Research

Instrumentation

Analytical Instrumentation

  • High Performance Liquid Chromatograpy (HPLC) – UV
  • Solid Phase Extraction system
  • Ion Chromatography (at the department)
  • Inductively Coupled Plasma Mass Spectrometer (at the department)
  • Microwave acid digestion (at the department)
  • Olympus Vanta Handheld X-Ray Fluorescence Spectrometer
  • Sonicator
  • Microbalance (XP2U model, Mettler Toledo)

Particulate Monitors 

  • Dusttrak DRX Aerosol Monitor (Model 8533, TSI Inc.) – Two
  • Personal Aerosol Monitor (Sidepak AM520, TSI Inc.) – Three
  • Personal DataRAM Aerosol monitor (pDR-1500, Thermo Scientific) – Three
  • Grimms portable aerosol spectrometer (Durag) – One
  • Particulate Monitor (E-Sampler, MetOne) – One
  • Air Quality Monitor (Dylos DC1700) – Six
  • Purple Air Sensors – ~20
  • Blue Sky Monitor (TSI Inc.) – One
  • Indoor Air Quality Monitor (Air Assure-8144-6, TSI Inc.) – Four
  • Indoor Air Quality Monitor (Q-Trak 7585, TSI Inc.) – One
  • Air Particle Counter (GT-526S, MetOne) – One
  • Ultrafine particle counter (Nanoparticle Monitor, Naneos Partector 2) – Two
  • Black carbon monitors (MA200 and AE51, Aeth Labs) – Three

Particulate Matter (PM) Samplers

  • PM particulate samplers (SKC PM2.5 and PM10 impactors and Leland Legacy Pumps) – Eight
  • PM particulate sampler (Tisch Low Volume Sampler and low volume calibrator) – One

Gas Monitors

  • Ozone monitor and ozone calibrator (Model 205 and Model 306, 2B Technologies)
  • NOx monitor (Model 405, 2B Technologies)
  • Indoor air quality meters (TPI 1010a)
  • Indoor Air Quality Monitor (Q-Trak 7585, TSI Inc.) – One
  • Passive samplers (Ogawa) – ~150

Weather Monitors

  • Weather monitor (Davis Vantage)
  • Weather monitor (Campbell Scientific)
  • HOBO – Four

Noise Monitors

  • Sound level meters (Model 831C, Larson Davis) – Two
  • Datalogging sound level meter (Model HD600, Extech) – One

Water Quality Monitors

  • Portable pH and Conductivity meter
  • Portable Colorimeter (Hach DR 900)

Air Pollution in Philadelphia

There is a high variability of air pollution in Philadelphia, both spatially and temporally. Overall, there is an improvement of air quality over the years. We used mobile monitoring using portable instruments to measure air pollution in Philadelphia.

Mobile Monitoring of Air Pollution in Philadelphia

  • Highest particulate matter (PM2.5) concentrations were found in Chestnut Hill neighborhood in Philadelphia.
  • Air pollution (PM2.5) hotspots were most prevalent in the North Delaware, River Wards, and North planning districts, particularly between 8:00 AM and 9:00 AM.
  • Factors such as traffic, urban structure, and industrial activity impact air quality in Philadelphia.

Publications

Long Term Trend of Particulate Matter in Philadelphia

  • PM10: Annual PM10 concentrations decreased by 47% from 1986 to 2021. Initially higher during summer months (1986-2000), but shifted to winter months (2011-2020).
  • PM2.5: Annual PM2.5 concentrations decreased by 31% from 2000 to 2021.  Significant reductions in summer PM2.5 concentrations were noted.
  • Carbonaceous Content: Both elemental carbon (EC) and organic carbon (OC) showed a decline from 2000 to 2021, contributing to overall PM2.5 reduction.
  • Environmental policies have been effective in reducing particulate matter (PM) concentrations in Philadelphia. Transportation-related policies were particularly impactful, leading to significant reductions in PM emissions. The transition from coal to natural gas for electricity generation also contributed to improved air quality.

Publication

Passive sampling of air pollution in Philadelphia

We used Ogawa passive samplers to measure nitrogen oxides (nitrogen dioxide and nitric oxide), ozone, ammonia, and sulfur dioxide at 15 sites across four counties (Philadelphia, Delaware, Montgomery, and Chester) from September 2021 to May 2022.

  • NOx: Higher concentrations at suburban (30.43 ± 33.79 ppb) and urban sites (22.49 ± 12.54 ppb) compared to semi-rural sites (11.08 ± 9.20 ppb).
  • SO2: Not detected in most measurements.
  • NH3: Highest concentrations in the winter (25.91 ppb). Positive correlation with NO in urban (R² = 0.33) and suburban sites (R² = 0.37), suggesting traffic emissions contribute to NH3 levels.
  • O3: Ozone concentrations were less variable among urban sites compared to suburban and semi-rural sites, suggesting more homogeneity in developed areas.

Publications

Air pollution in underground subways

There is higher exposure to particulate matter in underground subway stations compared to aboveground locations. Particulate matter levels can be about 5 to 8 times higher at belowground subway stations than the corresponding aboveground street level. Black carbon levels showed the highest
concentration at the belowground level by a factor of ten compared to the aboveground level. Station with the higher depth and more traffic, such as 15th Street had the highest PM levels.

Publications

Indoor Radon Levels in Pennsylvania

Radon is a radioactive gas that poses significant health risks, and is the leading cause of lung cancer among non-smokers in the United States. Radon exposure is the second leading cause of lung cancer in the United States, after smoking. Seasonal variations and housing characteristics significantly influence indoor radon levels. Understanding these factors can help in developing effective radon risk maps and mitigation strategies to reduce lung cancer risks associated with radon exposure.

  • Hotspots: Elevated radon levels were primarily found in south-central, central, and southeastern Pennsylvania.
  • Urban vs. Rural: Urban areas like Philadelphia and Pittsburgh had lower radon concentrations compared to rural areas.
  • Seasonal Trends: Radon levels were highest in winter and fall, and lowest in summer and spring. This variation is attributed to differences in ventilation and temperature.
  • Housing Types: Single-level homes had the highest radon concentrations, while apartments and townhouses had the lowest.
  • Floor Levels: Basement radon levels were significantly higher than ground floor levels.

Publication

Noise Pollution in Philadelphia

  • Noise levels showed significant temporal variation, with the highest levels generally observed during rush hours.
  • Among five different neighborhoods (Chestnut Hill, Tioga, Milcreek, Northern Liberties, and Center City), we found the highest environmental noise levels (68.00 ± 4.68 dBA) in the Center City.
  • Proximity to major roadways significantly influenced noise levels, with higher levels observed closer to major roads.

    Publication

Heavy Metal Pollution in Community Garden Soils

Community gardens are popular in urban cities such as Philadelphia and Pittsburgh. It provides several benefits to the residents. However, it is important to regularly soils for heavy metal contamination to prevent the risks at the sites with close proximity to past industrial legacies such as smelters and industries.

  • City areas in Philadelphia and Pittsburgh had higher elemental concentrations compared to suburban areas.
  • When compared to the more stringent Canadian Council of Ministers of the Environment (CCME) guidelines, 36% of Philadelphia gardens, 60% of Pittsburgh gardens, and 20% of Philadelphia suburban gardens exceeded the lead guideline of 140 mg/kg.
  • Elevated levels of lead and arsenic were found closer to historical smelting sites in Philadelphia.
  • Raised Beds vs. Unraised Beds: Raised beds had lower concentrations of lead and arsenic but higher concentrations of zinc, copper, vanadium, and nickel compared to unraised beds.

Publications

Environmental Justice

There is a disproportionate impact of environmental pollution in minority communities, and people with lower socioeconomic scores. Philadelphia has a high proportion of minority communities and have high level of poverty. It also has higher rates of asthma. In our study from summer 2017, neighborhoods with high minority communities do not appear to have high PM2.5 exposure during summer months. Some locations appear to be more vulnerable to air pollution. Higher asthma prevalence in Philadelphia was associated with greater PM2.5 and black carbon concentrations in spatial lag models.

We have also investigated the exposure to heavy metal contamination in community garden soils from Philadelphia and Norristown, which are also known as EJ community.

Publications

Air Pollution in Kathmandu Valley, Nepal

Kathmandu Valley, Nepal, faces significant air pollution challenges due to rapid urbanization, increased vehicle usage, and various industrial activities. The valley’s unique geography exacerbates the problem, trapping pollutants and leading to poor air quality. Air pollution in Kathmandu Valley is driven by multiple sources, including vehicle emissions, industrial activities, and biomass burning. 

  • PM2.5 and BC Concentrations (2014): Mean PM2.5 concentrations were 124.76 µg/m³ in spring and 45.92 µg/m³ during the monsoon. BC concentrations were 16.74 µgC/m³ in spring and 13.46 µgC/m³ during the monsoon among the measurement of traffic police’s exposure at five locations in Kathmandu Valley, Nepal.
  • PM2.5 concentrations were higher in winter (76 ± 18 µg/m³) compared to the monsoon season (21 ± 8 µg/m³). TSP and PM10 also showed seasonal variations at a residential location in Pulchowk, Kathmandu during 2014.
  • Chemical Composition: Silica, calcium, aluminum, and iron were the most abundant elements. Despite lower PM2.5 levels during the monsoon, BC and several elements remained high, indicating persistent vehicle emissions.
  • Diurnal Variability: PM2.5 and BC showed strong diurnal patterns with peaks during morning and evening rush hours.
  • Organic carbon (OC) and elemental carbon (EC) (2007-2008): Mean concentrations of organic carbon (OC) and elemental carbon (EC) were 20.02 µgC/m³ and 4.48 µgC/m³, respectively. Secondary organic carbon (SOC) contributed 31% to OC.
  • NO2, O3, and SO2: Urban sites had higher concentrations of NO2 and SO2 compared to suburban and rural sites. Ozone levels were higher in rural areas. NO2 and SO2 levels were higher in winter, while O3 levels were higher in summer.
  • Health Effects: High levels of PM2.5 and BC were associated with reduced lung function among traffic police workers in Kathmandu Valley. Non-smokers showed more significant declines in lung function compared to smokers.
  • Biomarkers: Fourteen biomarkers, including CRP, SAA, ICAM-1, VCAM-1, and various interleukins, were analyzed. Biomarker levels were higher in summer than in spring, despite lower PM2.5 levels in summer. Female traffic police had higher concentrations of several biomarkers compared to males. 
  • Protective Measures: Use of N95 masks reduced the adverse effects on lung function

Publications

Effectiveness of cloth masks to protect from air pollution

We compared the performance of cloth masks, bought at local markets in Kathmandu, Nepal with surgical masks and N95 masks. The design and fit of the mask significantly impact its performance. While cloth masks can reduce exposure to particulate matter to some extent, their effectiveness varies widely. Surgical masks and N95 masks offer better protection, but the choice of mask should be informed by the specific needs and availability. For individuals in highly polluted environments, selecting a more effective mask is crucial for reducing health risks.

  • Cloth Masks: Cloth mask with an exhaust valve performed best, with filtration efficiency of 80-90%. Ordinary cloth masks types had lower efficiency (39-65%), performing better for larger particle sizes.
  • Surgical Mask: Surgical mask performed much better compared to cloth masks.

Publication