Air change rates in stationary and moving motor vehicles

Fletcher, B.; Saunders, Caroline

doi:10.1016/0304-3894(94)90026-4

Cited by 29 publications

(19 citation statements)

References 2 publications

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“…Vehicles A and C each had a clearly marked ''recirculation control'' on the dashboard that could be set On or Off, but Vehicles B and D did not have recirculation controls. We concluded that setting the AC control, fan control, and recirculation control to Off on Vehicles A and C opened the fresh air vents without the mechanical ventilation system operating, which was the same as the passive ventilation case for the vehicles studied by Fletcher and Saunders (1994). We made 50 measurements of the ACH in Vehicles A and C for this passive ventilation case and the regression analysis gave a straight line was not too different from the empirical equation A ¼ 0.60V 1.25 developed by Fletcher and Saunders (see Figure 5).…”

Section: Passive Ventilation Statementioning

confidence: 80%

“…Park et al (1998) conclude that the air change rate of a vehicle is important for predicting the interior concentrations of pollutants. With the exception of Fletcher and Saunders (1994) and the measurements in Ott et al (1994), our literature review found no other published studies of ACHs in moving vehicles under different ventilation and window settings. Because of the importance of the vehicle's air change rate for exposure analysis, we made new measurements of the ACHs of 4 motor vehicles under a variety of conditions.…”

mentioning

confidence: 89%

“…With recirculation system off (vent open), the ACH will follow the empirical equation for the vehicle's speed proposed by Fletcher and Saunders (1994) A main study goal was to provide new data on the ventilation rates of motor vehicles under both stationary and moving conditions. We also hoped to verify the high particle concentrations for smoking predicted by Ott et al (1992) and by Park et al (1998).…”

Section: Approachmentioning

confidence: 99%

“…Our straight-line regression equation A ¼ 0.62 VÀ3.4 covered a speed range from 15 to 72 mph, giving an observed ACH ranging from 5.9 to 41.2 h À1 . Because we could not set the controls on Vehicles B and D to a similar passive ventilation state (recirculation off and no fan operating), we could not test the empirical equation of Fletcher and Saunders (1994) on these two vehicles.…”

Section: Passive Ventilation Statementioning

confidence: 99%

“…With the driver's window fully open and the front passenger window open 3 00 (1.2 cm), they measured an ACH ranging from 60 to 120 h À1 . Fletcher and Saunders (1994) studied the air change rates of five vehicles for different wind speeds and wind directions. They determined leakage characteristics with the vents open and with them closed.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Air change rates of motor vehicles and in-vehicle pollutant concentrations from secondhand smoke

Ott

Klepeis

Switzer

2007

J Expo Sci Environ Epidemiol

159

175

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The air change rates of motor vehicles are relevant to the sheltering effect from air pollutants entering from outside a vehicle and also to the interior concentrations from any sources inside its passenger compartment. We made more than 100 air change rate measurements on four motor vehicles under moving and stationary conditions; we also measured the carbon monoxide (CO) and fine particle (PM 2.5 ) decay rates from 14 cigarettes smoked inside the vehicle. With the vehicle stationary and the fan off, the ventilation rate in air changes per hour (ACH) was less than 1 h À1 with the windows closed and increased to 6.5 h À1 with one window fully opened. The vehicle speed, window position, ventilation system, and air conditioner setting was found to affect the ACH. For closed windows and passive ventilation (fan off and no recirculation), the ACH was linearly related to the vehicle speed over the range from 15 to 72 mph (25 to 116 km h À1 ). With a vehicle moving, windows closed, and the ventilation system off (or the air conditioner set to AC Max), the ACH was less than 6.6 h À1 for speeds ranging from 20 to 72 mph (32 to 116 km h À1 ). Opening a single window by 3 00 (7.6 cm) increased the ACH by 8-16 times. For the 14 cigarettes smoked in vehicles, the deposition rate k and the air change rate a were correlated, following the equation k ¼ 1.3a (R 2 ¼ 82%; n ¼ 14). With recirculation on (or AC Max) and closed windows, the interior PM 2.5 concentration exceeded 2000 mg mÀ3 momentarily for all cigarettes tested, regardless of speed. The concentration time series measured inside the vehicle followed the mathematical solutions of the indoor mass balance model, and the 24-h average personal exposure to PM 2.5 could exceed 35 mg m À3 for just two cigarettes smoked inside the vehicle.

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Section: Passive Ventilation Statementioning

confidence: 80%

mentioning

confidence: 89%

Section: Approachmentioning

confidence: 99%

Section: Passive Ventilation Statementioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Air change rates of motor vehicles and in-vehicle pollutant concentrations from secondhand smoke

Ott

Klepeis

Switzer

2007

J Expo Sci Environ Epidemiol

159

175

View full text Add to dashboard Cite

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Automobile Air Conditioning Loads Modelling Using Heat Balance Method

Wagh

Parekh

2023

Lecture Notes in Mechanical Engineering

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Size-resolved simulation of particulate matters and CO2 concentration in passenger vehicle cabins

Wei

Nielsen

Ekberg

et al. 2022

Environ Sci Pollut Res

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The main aim of this study is to develop a mathematical size-dependent vehicle cabin model for particulate matter concentration including PM2.5 (particles of aerodynamic diameter less than 2.5 μm) and UFPs (ultrafine particles of aerodynamic diameter less than 100 nm), as well as CO2 concentration. The ventilation airflow rate and cabin volume parameters are defined from a previously developed vehicle model for climate system design. The model simulates different filter statuses, application of pre-ionization, different airflow rates and recirculation degrees. Both particle mass and count concentration within 10–2530 nm are simulated. Parameters in the model are defined from either available component test data (for example filter efficiencies) or assumptions from corresponding studies (for example particle infiltration and deposition rates). To validate the model, road measurements of particle and CO2 concentrations outside two vehicles were used as model inputs. The simulated inside PM2.5, UFP and CO2 concentration were compared with the inside measurements. Generally, the simulation agrees well with measured data (Person’s r 0.89–0.92), and the simulation of aged filter with ionization is showing higher deviation than others. The simulation using medium airflows agrees better than the simulation using other airflows, both lower and higher. The reason for this may be that the filter efficiency data used in the model were obtained at airflows close to the medium airflow. When all size bins are compared, the sizes of 100–300 nm were slightly overestimated. The results indicated that among others, expanded filter efficiency data as a function of filter ageing and airflow rate would possibly enhance the simulation accuracy. An initial application sample study on recirculation degrees presents the model’s possible application in developing advanced climate control strategies.

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Air change rates in stationary and moving motor vehicles

Cited by 29 publications

References 2 publications

Air change rates of motor vehicles and in-vehicle pollutant concentrations from secondhand smoke

Air change rates of motor vehicles and in-vehicle pollutant concentrations from secondhand smoke

Automobile Air Conditioning Loads Modelling Using Heat Balance Method

Size-resolved simulation of particulate matters and CO2 concentration in passenger vehicle cabins

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