Flight path optimization is designed for minimizing environmental impacts of aircraft around airports during approaches. The main objective of this paper is to develop a model of optimal flight paths taking into account jet noise, fuel consumption, constraints and extreme operational limits of the aircraft in approach. A two-segment approach is obtained as an optimal trajectory. Aircraft alignment on the runway axis with a slope of 3° during the last approach segment is observed and the descent rate is about 1060 ft/mn. This particularly characterizes the continuous descent approach having the potential to reduce noise emission by −4 dB and fuel consumption by −20 % to −10 % during the approach. Measurements of aircraft noise were carried out around Saint-Exupry Lyon International Airport for one year. Because of the suggested trajectory, optimized noise levels are less than the measured and INM values. Optimal trajectory consumes less than the standard trajectory; it can be integrated in the aircraft FMS and used in the autopilot system. This is one of the promising objectives of this research.

Non-exhaust road transport emissions in cities contribute to poor air quality and have an impact on human health. This paper presents a new study of particles emitted by tyre wear in real driving conditions and gives their emission factors. The most frequently emitted particles were collected in urban, suburban and road areas. They were identified and analysed physically and chemically. Their level of toxicity is well known. An overall analysis of the measured pollutants was carried out to assess their emission factors in real driving situations. The highest emitting pollutants, considered separately, were found to have high emission factors. The values obtained exceed the Euro standard for vehicles but are below those of vehicles not equipped with particle filters. Significant test analysis confirmed that the inertia of chemical pollutants is homogeneous. Emission factors have also been provided for PM₁₀ and PM_2.5. These results should contribute to the emergence of future regulations of non-exhaust emissions and should help to analyse the exposure-impact relationship for particles from tyre wear.

Emerging African countries are characterized by explosive population growth and urbanization, which threaten environmental sustainability. This study comparatively characterized ambient aerosols and assessed cytotoxicity to facilitate improving health and environmental policy. Twenty-four air samples were collected at high and low-density traffic sites in Kano State using polysulfone and stainless steel filters attached to an automated pump. The physico-chemical properties of particulate matter were determined using scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX). In vitro, their potential toxicity was assessed using macrophages and cell fixation with staining. Results showed 51.7% of particles as PM_2.5, with the highest particle concentration in mixed sites (urban and industrial). Particle classification into four groups by elemental composition and structure showed: sand particles (Si, Al, Fe, Ca, Mg, K, Na, Mo, Sr, Zr) 30–51%; other fibers 0–3%; other particles (Si, Fe, S, Mo, Zn, and other metals) 22–40%; and silicone-based fibres 23–34%. The abundant elements are: Si, Al, Ca, Ce, Ti, Fe, Cl, Pb, and Mn. The lowest viability on cytotoxicity assessment was recorded in mixed site M2. The majority of households were located within 50 m of air sampling sites. Proximity to traffic sites worsens health, as evidenced in cytotoxicity findings. We recommend improved urban planning and intensification of emissions control.

Emerging African countries are characterized by explosive population growth and urbanization, which threaten environmental sustainability. This study comparatively characterized ambient aerosols and assessed cytotoxicity to facilitate improving health and environmental policy. Twenty-four air samples were collected at high and low-density traffic sites in Kano State using polysulfone and stainless steel filters attached to an automated pump. The physico-chemical properties of particulate matter were determined using scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX). In vitro, their potential toxicity was assessed using macrophages and cell fixation with staining. Results showed 51.7% of particles as PM_2.5, with the highest particle concentration in mixed sites (urban and industrial). Particle classification into four groups by elemental composition and structure showed: sand particles (Si, Al, Fe, Ca, Mg, K, Na, Mo, Sr, Zr) 30–51%; other fibers 0–3%; other particles (Si, Fe, S, Mo, Zn, and other metals) 22–40%; and silicone-based fibres 23–34%. The abundant elements are: Si, Al, Ca, Ce, Ti, Fe, Cl, Pb, and Mn. The lowest viability on cytotoxicity assessment was recorded in mixed site M2. The majority of households were located within 50 m of air sampling sites. Proximity to traffic sites worsens health, as evidenced in cytotoxicity findings. We recommend improved urban planning and intensification of emissions control.

Transport systems (road, railway and aircraft traffic) are the main contributors to poor air quality in the major cities

Non-exhaust road transport emissions in cities contribute to poor air quality and create health impacts. This paper presents a new study of the emitted particles due to the tyres-road wear ‘TRWP’ in real driving and gives their emission factors EF. The most frequently observed particles were <1 µm; followed by particles size between [1µm, 4µm] for urban, suburban and highway areas. These particle sizes are well-known to have a higher degree of toxicity. An overall analysis of all the measured pollutants gave EF equal to 30 10+12 #/km and 35 10+12 #/km, respectively for urban and sub-urban areas; and 5 10+12 #/km on highway. The analysis of the 19 most emitted pollutants, taken individually, showed that their EFs ranged from 0.003 to 18.142 10+12#/km. The obtained EF are above the value of the Euro standard for vehicles, but are below the values for vehicles unequipped with a particle filter. Significant test analysis confirmed that inertia of chemical pollutants is homogeneous. EF assessment of the PM10 and PM2.5 emitted is equal to 1.45 mg/km and 0.35 mg/km respectively. These results should contribute to the emergence of future regulations of non-exhaust emissions and should help to analyse the exposure-impact relationship to TRWP.