Related Experiment Video
Updated: May 2, 2026
07:12
Façade-Level Monitoring of CO2 Variability under Urban Heat Island Conditions using Low-Cost Sensor Data Loggers
Published on: December 12, 2025
377
Spatial variation in ambient benzene concentrations over a city park
Journal of Environmental Health
|March 21, 2014
Summary
This study measured ambient benzene levels in a Tampa park using passive samplers. Spatial variations were minimal, contributing less to health risk uncertainty than other factors.
Area of Science:
- Environmental Science
- Air Quality Monitoring
- Toxicology
Background:
- Benzene is a common air pollutant with known health risks.
- Accurate exposure assessment is crucial for health risk evaluation.
- Understanding spatial variability of pollutants is key for urban air quality management.
Purpose of the Study:
- To assess ambient benzene concentrations in a city park.
- To evaluate the spatial variability of benzene within the park.
- To determine the contribution of spatial variability to health risk assessment uncertainty.
Main Methods:
- Passive diffusive samplers deployed for one week at 11 park locations.
- Gas chromatography with mass spectrometry used for benzene quantification.
- Analysis of spatial variability and its impact on health risk estimates.
Main Results:
- Measured benzene concentrations ranged from 0.23 to 0.34 µg/m³.
- Low spatial variability observed, with an 11% coefficient of variation.
- Sampler collocation showed good agreement (3% and 14% RPD).
Conclusions:
- Spatial variability of ambient benzene in the park is small.
- Sampler placement uncertainty contributes less to health risk uncertainty than inhalation unit risk.
- Limited spatial resolution is sufficient for health risk calculations in such areas.
Related Concept Videos
01:37NMR Spectroscopy of Benzene Derivatives
10.3K
Simple unsubstituted benzene has six aromatic protons, all chemically equivalent. Therefore, benzene exhibits only a singlet peak at δ 7.3 ppm in the 1H NMR spectrum. The observed shift is far downfield because the aromatic ring current strongly deshields the protons. Any substitution on the benzene ring makes the aromatic protons nonequivalent, and the protons split each other. The peak is, therefore, no longer a singlet and the splitting pattern and their associated coupling...
10.3K
01:18Structure of Benzene: Molecular Orbital Model
11.4K
According to the molecular orbital (MO) model, benzene has a planar structure with a regular hexagon of six sp2 hybridized carbons. As shown in Figure 1, each carbon is bonded to three other atoms with C–C–C and H–C–C bond angles of 120°. The C–H bond length is 109 pm, and the C–C bond length is 139 pm which is midway between the single bond length of sp3 hybridized carbons (154 pm) and sp2 hybridized carbons (133 pm).
11.4K
01:14π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds
1.7K
In aromatic compounds, such as benzene, the circulation of (4n + 2) π-electrons sets up a diamagnetic or diatropic ring current around the perimeter of the molecule. This current induces a magnetic field that opposes the external field inside the ring and reinforces it on the outside. The protons in benzene are deshielded and exhibit high chemical shifts in the range 6.5–8.5 ppm. The shielding effect at the center of the ring is evident in complex aromatic molecules, such as...
1.7K
01:07Structure of Benzene: Kekulé Model
9.1K
In 1865, August Kekule suggested the structure of benzene according to the structural theory of organic chemistry based on the three assertions—formula of benzene is C6H6, all the hydrogens of benzene are equivalent, and each carbon must have four bonds due to its tetravalency.
He proposed that benzene has a cyclic structure of six carbon atoms attached to one hydrogen atom each, with three alternating pi bonds.
He proposed that benzene has a cyclic structure of six carbon atoms attached to one hydrogen atom each, with three alternating pi bonds.
9.1K
01:25Aromatic Compounds: Overview
11.8K
In general, the term ‘aromatic’ indicates a pleasant smell or fragrance from fresh flowers, freshly prepared coffee, etc. In the early history of organic chemistry, many benzene derivatives were isolated from the pleasant odor oils of the plants. For example, vanillin was isolated from the oil of vanilla, methyl salicylate from the oil of wintergreen, and cinnamaldehyde from the oil of cinnamon. They all had a pleasant odor; hence the name aromatic was given.
In 1825, Faraday...
In 1825, Faraday...
11.8K
01:22Electrophilic Aromatic Substitution: Sulfonation of Benzene
6.5K
Sulfonation of benzene is a reaction wherein benzene is treated with fuming sulfuric acid at room temperature to produce benzenesulfonic acid. Fuming sulfuric acid is a mixture of sulfur trioxide and concentrated sulfuric acid.
6.5K